Communication systems are well known and consist of many types including land mobile radio, cellular radiotelephone, personal communication systems, and other communication system types. Within a communication system, transmissions are conducted between a transmitting device and a receiving device over a communication resource, commonly referred to as a communication channel, To date, the transmissions have typically consisted of voice signals. More recently, however, it has been proposed to carry other forms of signals, including high-speed data signals. For ease of operation, it is preferable to have the data transmission capability overlay the existing voice communication capability, such that its operation is essentially transparent to the voice communication system while still utilizing the communication resources and other infrastructure of the voice communication system.
One such communication system currently being developed with transparent data transmission capabilities is the next generation Code-Division Multiple-Access (CDMA) cellular communication system, more commonly referred to as Universal Mobile Telecommunications System (UMTS) Wideband cdma, or cdma2000. Remote unit data transmission within a Wideband communication system takes place by assigning the remote unit a high-speed data channel (referred to as a dedicated data channel) and transmitting data utilizing the dedicated data channel.
Typically, as a remote unit moves to a periphery of a serving base site coverage area, the transmit power of the communication unit as well as the transmit power of the base site must be increased to account for an increase in path losses between the serving base site and the remote unit. Even with the increase in transmit power, oftentimes an increase in system interference/noise will prevent data transmission between the remote unit and the base station at higher data rates. More particularly, even though transmissions between the remote unit and the base station occur utilizing high-speed data channels, the retransmission of data due to increased system interference effectively reduces the data rate of the dedicated data channels. The continued high-speed data transmission, and subsequent retransmission, contribute to overall system interference. Additionally, for downlink transmissions there exists a shortage of available channels to utilize in the transmission of data from the base station. The continued transmission and retransmission of data occupies the dedicated data channels for lengthy periods of time. Therefore a need exists for a method and apparatus for data transmission within a communication system that does not occupy dedicated data channels for lengthy periods of time, and does not contribute to overall system interference when an system noise prevents high-speed data transmission.